The structure and function of several proteins or groups of proteins will be examined in order to determine the structural basis of their biological activities. Three major groups of proteins will be studied. 1) Glycosyl transferases that are involved in the biosynthesis of the oligosaccharides of mammalian glycoproteins will be isolated in homogeneous forms and their structural properties and specific enzymic properties determined. Their role in regulating oligosaccharide synthesis and the possibility that they form multienzyme complexes in vivo will be assessed. 2) Rabbit and chicken liver lectins that bind either galactosyl or N-acetylglucosaminyl residues in plasma proteins and aid in plasma protein turnover will be studied. The complete amino acid sequence of the chicken lectin and considerable portions of the rabbit lectin will be determine. 3) Glycoproteins will be studied including salivary and gastric mucins and erythrocyte membrane glycoproteins. The mucins contain 60-85% carbohydrate and attepts will be made to assess how carbohydrate interactions determine the properties of these important biological lubricants. The red cell wall glycoproteins will be labeled with radioactive sugars with aid of glycosyl transferases in order to assess which proteins contribute blood group antigenic determinants. Particular attention will be devoted towards use of glycosyl transferases and glycosidases in the structural analysis of glycoproteins.